Final answer:
The main advantages of third- and fourth-generation penicillins include increased resistance to enzymatic inactivation, broader spectrum of activity, and greater diversity in chemical alterations. Third-generation cephalosporins have increased resistance to ß-lactamases, broad-spectrum activity, and the ability to penetrate the central nervous system.
Step-by-step explanation:
The main advantages of the third- and fourth-generation penicillins include:
- Increased resistance to enzymatic inactivation by ß-lactamases due to the fused six-member ring in their ß-lactam ring structure.
- Broader spectrum of activity, especially against gram-negative bacteria, compared to earlier generations of penicillins.
- Greater diversity in chemical alterations and development of semisynthetic penicillins due to the presence of two R groups in cephalosporin C.
Third-generation cephalosporins have the following advantages:
- Increased resistance to ß-lactamases due to structural modifications.
- Broad-spectrum activity against both Gram-positive and -negative bacteria.
- Ability to penetrate the central nervous system, making them effective against meningitis.